The present invention is directed to apparatus for forming tubular parts from relatively small diameter metal tubing, as for use in automotive vacuum systems, for example.
In such systems, it is quite common to connect a length of tubing to a relatively short inlet or outlet tube projecting from the housing of a circuit component by radially expanding the end of the length of tubing until it can be slipped onto and braized to the inlet or outlet fitting. Clearance problems frequently require that the length of tubing be bent close to the large diameter end section. Formation of tubular parts of this last configuration, which have an enlarged diameter section at one end and a bend, typically 90 degrees, in the tube adjacent this enlarged diameter end section, have presented a problem, particularly when such parts are to be produced on a mass production basis.
The tubing employed is typically a relatively soft maleable steel which does not present any large problem in forming the enlarged diameter end section or in forming a bend in the tubing except in the case where it is desired to form the bend closely adjacent the enlarged diameter end section. The enlargement and bending are most efficiently performed in two steps, normally by bending the tube after the end has been enlarged. When the bend must be performed at a location close to the enlarged diameter section, the formation of the bend will distort the enlarged section resulting in a poor fit between the enlarged section and the tube to which it is to be fitted.
The present invention is especially directed to a tube forming apparatus which enables the formation of a relatively short radius bend immediately adjacent and in fact merging tangentially with an enlarged end section of the tubing.